采用有限元方法建立和分析枢椎的生物力学行为

Establishment and analysis of a three-dimensional finite element model of human Axis(C2)

目的采取有限元的方法,建立第二颈椎(枢椎)的三维有限元模型,模拟该枢椎模型在外力作用下的生物力学行为,分析枢椎骨折的生物力学条件。方法利用螺旋CT扫描获得健康成年男性上颈椎原始DICOM数据图像,采用Mimics软件对数据进行处理并导入ANSYS软件,得到枢椎骨性结构的三维实体模型。并且此模型上模拟头颅位于中立位、屈曲位及后伸位等条件下,枢椎承受的应力分布状况,分析枢椎可能出现的骨折类型。结果实验所构建枢椎骨性的有限元模型外形逼真,三维网格化后枢椎模型共包含1 717个节点,5 772个单元。模拟结果:头颅在中立、前屈、后伸位时枢椎最大应力集中于齿突基底部,次级应力集中区域为枢椎椎弓峡部;直接于齿突加载力模拟头部过度屈曲时,最大应力集中于齿突基底部。结论头颅位于中立位,屈曲位或者后伸位,枢椎齿突基底部及枢椎椎弓峡部是应力最集中的部位。头部过度屈曲时,齿突基底部是应力最集中的部位。

Objective To establish the Axis finite element model with three -dimensional finite element method, and make the pre- liminary biomechanical analysis by using this model. Methods DICOM image data of the cervical spine of a healthy adult man were obtained by spiral CT and processed with Mimics software. The data were imported to ANSYS software to become a 3D entity. Based on the model of axis, the stress different position of axis was analysis while skull was in neutral, flexion and posterior extension position. Results The Axis finite element model included 1,717 nodes and 5,772 units, and consistent with the biomechanical analysis. The model was in good running under external force. In the model of Axis, when load forced on superior articular facet of axis, the biggest Von Mises stress focused on the base of Dens and the smaller was on the stenosis of cervical arch. When the load forced on Dens and skull in exeessive flexion, the biggest stress significantly focused on the base of Dens. Conclusion The finite element model of Axis can simulate natural condition of cervical spine and facilitate the further biomechanical research. While skull was in neutral, flexion and posterior extension position, the stress focused on the base of Dens and the stenosis of cervical arch, but when head is in excessive flexion, the biggest stress force focused on the base of Dens.